/*
 * Copyright (c) 1995, 2013, Oracle and/or its affiliates. All rights reserved.
 * ORACLE PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 *
 *
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 *
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 *
 *
 *
 */

package java.net;

import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.io.FileDescriptor;

import sun.net.ConnectionResetException;
import sun.net.NetHooks;
import sun.net.ResourceManager;

/**
 * Default Socket Implementation. This implementation does
 * not implement any security checks.
 * Note this class should <b>NOT</b> be public.
 *
 * @author Steven B. Byrne
 */
abstract class AbstractPlainSocketImpl extends SocketImpl {

  /* instance variable for SO_TIMEOUT */
  int timeout;   // timeout in millisec
  // traffic class
  private int trafficClass;

  private boolean shut_rd = false;
  private boolean shut_wr = false;

  private SocketInputStream socketInputStream = null;
  private SocketOutputStream socketOutputStream = null;

  /* number of threads using the FileDescriptor */
  protected int fdUseCount = 0;

  /* lock when increment/decrementing fdUseCount */
  protected final Object fdLock = new Object();

  /* indicates a close is pending on the file descriptor */
  protected boolean closePending = false;

  /* indicates connection reset state */
  private int CONNECTION_NOT_RESET = 0;
  private int CONNECTION_RESET_PENDING = 1;
  private int CONNECTION_RESET = 2;
  private int resetState;
  private final Object resetLock = new Object();

  /* whether this Socket is a stream (TCP) socket or not (UDP)
   */
  protected boolean stream;

  /**
   * Load net library into runtime.
   */
  static {
    java.security.AccessController.doPrivileged(
        new java.security.PrivilegedAction<Void>() {
          public Void run() {
            System.loadLibrary("net");
            return null;
          }
        });
  }

  /**
   * Creates a socket with a boolean that specifies whether this
   * is a stream socket (true) or an unconnected UDP socket (false).
   */
  protected synchronized void create(boolean stream) throws IOException {
    this.stream = stream;
    if (!stream) {
      ResourceManager.beforeUdpCreate();
      // only create the fd after we know we will be able to create the socket
      fd = new FileDescriptor();
      try {
        socketCreate(false);
      } catch (IOException ioe) {
        ResourceManager.afterUdpClose();
        fd = null;
        throw ioe;
      }
    } else {
      fd = new FileDescriptor();
      socketCreate(true);
    }
    if (socket != null) {
      socket.setCreated();
    }
    if (serverSocket != null) {
      serverSocket.setCreated();
    }
  }

  /**
   * Creates a socket and connects it to the specified port on
   * the specified host.
   *
   * @param host the specified host
   * @param port the specified port
   */
  protected void connect(String host, int port)
      throws UnknownHostException, IOException {
    boolean connected = false;
    try {
      InetAddress address = InetAddress.getByName(host);
      this.port = port;
      this.address = address;

      connectToAddress(address, port, timeout);
      connected = true;
    } finally {
      if (!connected) {
        try {
          close();
        } catch (IOException ioe) {
                    /* Do nothing. If connect threw an exception then
                       it will be passed up the call stack */
        }
      }
    }
  }

  /**
   * Creates a socket and connects it to the specified address on
   * the specified port.
   *
   * @param address the address
   * @param port the specified port
   */
  protected void connect(InetAddress address, int port) throws IOException {
    this.port = port;
    this.address = address;

    try {
      connectToAddress(address, port, timeout);
      return;
    } catch (IOException e) {
      // everything failed
      close();
      throw e;
    }
  }

  /**
   * Creates a socket and connects it to the specified address on
   * the specified port.
   *
   * @param address the address
   * @param timeout the timeout value in milliseconds, or zero for no timeout.
   * @throws IOException if connection fails
   * @throws IllegalArgumentException if address is null or is a SocketAddress subclass not
   * supported by this socket
   * @since 1.4
   */
  protected void connect(SocketAddress address, int timeout)
      throws IOException {
    boolean connected = false;
    try {
      if (address == null || !(address instanceof InetSocketAddress)) {
        throw new IllegalArgumentException("unsupported address type");
      }
      InetSocketAddress addr = (InetSocketAddress) address;
      if (addr.isUnresolved()) {
        throw new UnknownHostException(addr.getHostName());
      }
      this.port = addr.getPort();
      this.address = addr.getAddress();

      connectToAddress(this.address, port, timeout);
      connected = true;
    } finally {
      if (!connected) {
        try {
          close();
        } catch (IOException ioe) {
                    /* Do nothing. If connect threw an exception then
                       it will be passed up the call stack */
        }
      }
    }
  }

  private void connectToAddress(InetAddress address, int port, int timeout) throws IOException {
    if (address.isAnyLocalAddress()) {
      doConnect(InetAddress.getLocalHost(), port, timeout);
    } else {
      doConnect(address, port, timeout);
    }
  }

  public void setOption(int opt, Object val) throws SocketException {
    if (isClosedOrPending()) {
      throw new SocketException("Socket Closed");
    }
    boolean on = true;
    switch (opt) {
            /* check type safety b4 going native.  These should never
             * fail, since only java.Socket* has access to
             * PlainSocketImpl.setOption().
             */
      case SO_LINGER:
        if (val == null || (!(val instanceof Integer) && !(val instanceof Boolean))) {
          throw new SocketException("Bad parameter for option");
        }
        if (val instanceof Boolean) {
                /* true only if disabling - enabling should be Integer */
          on = false;
        }
        break;
      case SO_TIMEOUT:
        if (val == null || (!(val instanceof Integer))) {
          throw new SocketException("Bad parameter for SO_TIMEOUT");
        }
        int tmp = ((Integer) val).intValue();
        if (tmp < 0) {
          throw new IllegalArgumentException("timeout < 0");
        }
        timeout = tmp;
        break;
      case IP_TOS:
        if (val == null || !(val instanceof Integer)) {
          throw new SocketException("bad argument for IP_TOS");
        }
        trafficClass = ((Integer) val).intValue();
        break;
      case SO_BINDADDR:
        throw new SocketException("Cannot re-bind socket");
      case TCP_NODELAY:
        if (val == null || !(val instanceof Boolean)) {
          throw new SocketException("bad parameter for TCP_NODELAY");
        }
        on = ((Boolean) val).booleanValue();
        break;
      case SO_SNDBUF:
      case SO_RCVBUF:
        if (val == null || !(val instanceof Integer) ||
            !(((Integer) val).intValue() > 0)) {
          throw new SocketException("bad parameter for SO_SNDBUF " +
              "or SO_RCVBUF");
        }
        break;
      case SO_KEEPALIVE:
        if (val == null || !(val instanceof Boolean)) {
          throw new SocketException("bad parameter for SO_KEEPALIVE");
        }
        on = ((Boolean) val).booleanValue();
        break;
      case SO_OOBINLINE:
        if (val == null || !(val instanceof Boolean)) {
          throw new SocketException("bad parameter for SO_OOBINLINE");
        }
        on = ((Boolean) val).booleanValue();
        break;
      case SO_REUSEADDR:
        if (val == null || !(val instanceof Boolean)) {
          throw new SocketException("bad parameter for SO_REUSEADDR");
        }
        on = ((Boolean) val).booleanValue();
        break;
      default:
        throw new SocketException("unrecognized TCP option: " + opt);
    }
    socketSetOption(opt, on, val);
  }

  public Object getOption(int opt) throws SocketException {
    if (isClosedOrPending()) {
      throw new SocketException("Socket Closed");
    }
    if (opt == SO_TIMEOUT) {
      return new Integer(timeout);
    }
    int ret = 0;
        /*
         * The native socketGetOption() knows about 3 options.
         * The 32 bit value it returns will be interpreted according
         * to what we're asking.  A return of -1 means it understands
         * the option but its turned off.  It will raise a SocketException
         * if "opt" isn't one it understands.
         */

    switch (opt) {
      case TCP_NODELAY:
        ret = socketGetOption(opt, null);
        return Boolean.valueOf(ret != -1);
      case SO_OOBINLINE:
        ret = socketGetOption(opt, null);
        return Boolean.valueOf(ret != -1);
      case SO_LINGER:
        ret = socketGetOption(opt, null);
        return (ret == -1) ? Boolean.FALSE : (Object) (new Integer(ret));
      case SO_REUSEADDR:
        ret = socketGetOption(opt, null);
        return Boolean.valueOf(ret != -1);
      case SO_BINDADDR:
        InetAddressContainer in = new InetAddressContainer();
        ret = socketGetOption(opt, in);
        return in.addr;
      case SO_SNDBUF:
      case SO_RCVBUF:
        ret = socketGetOption(opt, null);
        return new Integer(ret);
      case IP_TOS:
        try {
          ret = socketGetOption(opt, null);
          if (ret == -1) { // ipv6 tos
            return trafficClass;
          } else {
            return ret;
          }
        } catch (SocketException se) {
          // TODO - should make better effort to read TOS or TCLASS
          return trafficClass; // ipv6 tos
        }
      case SO_KEEPALIVE:
        ret = socketGetOption(opt, null);
        return Boolean.valueOf(ret != -1);
      // should never get here
      default:
        return null;
    }
  }

  /**
   * The workhorse of the connection operation.  Tries several times to
   * establish a connection to the given <host, port>.  If unsuccessful,
   * throws an IOException indicating what went wrong.
   */

  synchronized void doConnect(InetAddress address, int port, int timeout) throws IOException {
    synchronized (fdLock) {
      if (!closePending && (socket == null || !socket.isBound())) {
        NetHooks.beforeTcpConnect(fd, address, port);
      }
    }
    try {
      acquireFD();
      try {
        socketConnect(address, port, timeout);
                /* socket may have been closed during poll/select */
        synchronized (fdLock) {
          if (closePending) {
            throw new SocketException("Socket closed");
          }
        }
        // If we have a ref. to the Socket, then sets the flags
        // created, bound & connected to true.
        // This is normally done in Socket.connect() but some
        // subclasses of Socket may call impl.connect() directly!
        if (socket != null) {
          socket.setBound();
          socket.setConnected();
        }
      } finally {
        releaseFD();
      }
    } catch (IOException e) {
      close();
      throw e;
    }
  }

  /**
   * Binds the socket to the specified address of the specified local port.
   *
   * @param address the address
   * @param lport the port
   */
  protected synchronized void bind(InetAddress address, int lport)
      throws IOException {
    synchronized (fdLock) {
      if (!closePending && (socket == null || !socket.isBound())) {
        NetHooks.beforeTcpBind(fd, address, lport);
      }
    }
    socketBind(address, lport);
    if (socket != null) {
      socket.setBound();
    }
    if (serverSocket != null) {
      serverSocket.setBound();
    }
  }

  /**
   * Listens, for a specified amount of time, for connections.
   *
   * @param count the amount of time to listen for connections
   */
  protected synchronized void listen(int count) throws IOException {
    socketListen(count);
  }

  /**
   * Accepts connections.
   *
   * @param s the connection
   */
  protected void accept(SocketImpl s) throws IOException {
    acquireFD();
    try {
      socketAccept(s);
    } finally {
      releaseFD();
    }
  }

  /**
   * Gets an InputStream for this socket.
   */
  protected synchronized InputStream getInputStream() throws IOException {
    synchronized (fdLock) {
      if (isClosedOrPending()) {
        throw new IOException("Socket Closed");
      }
      if (shut_rd) {
        throw new IOException("Socket input is shutdown");
      }
      if (socketInputStream == null) {
        socketInputStream = new SocketInputStream(this);
      }
    }
    return socketInputStream;
  }

  void setInputStream(SocketInputStream in) {
    socketInputStream = in;
  }

  /**
   * Gets an OutputStream for this socket.
   */
  protected synchronized OutputStream getOutputStream() throws IOException {
    synchronized (fdLock) {
      if (isClosedOrPending()) {
        throw new IOException("Socket Closed");
      }
      if (shut_wr) {
        throw new IOException("Socket output is shutdown");
      }
      if (socketOutputStream == null) {
        socketOutputStream = new SocketOutputStream(this);
      }
    }
    return socketOutputStream;
  }

  void setFileDescriptor(FileDescriptor fd) {
    this.fd = fd;
  }

  void setAddress(InetAddress address) {
    this.address = address;
  }

  void setPort(int port) {
    this.port = port;
  }

  void setLocalPort(int localport) {
    this.localport = localport;
  }

  /**
   * Returns the number of bytes that can be read without blocking.
   */
  protected synchronized int available() throws IOException {
    if (isClosedOrPending()) {
      throw new IOException("Stream closed.");
    }

        /*
         * If connection has been reset or shut down for input, then return 0
         * to indicate there are no buffered bytes.
         */
    if (isConnectionReset() || shut_rd) {
      return 0;
    }

        /*
         * If no bytes available and we were previously notified
         * of a connection reset then we move to the reset state.
         *
         * If are notified of a connection reset then check
         * again if there are bytes buffered on the socket.
         */
    int n = 0;
    try {
      n = socketAvailable();
      if (n == 0 && isConnectionResetPending()) {
        setConnectionReset();
      }
    } catch (ConnectionResetException exc1) {
      setConnectionResetPending();
      try {
        n = socketAvailable();
        if (n == 0) {
          setConnectionReset();
        }
      } catch (ConnectionResetException exc2) {
      }
    }
    return n;
  }

  /**
   * Closes the socket.
   */
  protected void close() throws IOException {
    synchronized (fdLock) {
      if (fd != null) {
        if (!stream) {
          ResourceManager.afterUdpClose();
        }
        if (fdUseCount == 0) {
          if (closePending) {
            return;
          }
          closePending = true;
                    /*
                     * We close the FileDescriptor in two-steps - first the
                     * "pre-close" which closes the socket but doesn't
                     * release the underlying file descriptor. This operation
                     * may be lengthy due to untransmitted data and a long
                     * linger interval. Once the pre-close is done we do the
                     * actual socket to release the fd.
                     */
          try {
            socketPreClose();
          } finally {
            socketClose();
          }
          fd = null;
          return;
        } else {
                    /*
                     * If a thread has acquired the fd and a close
                     * isn't pending then use a deferred close.
                     * Also decrement fdUseCount to signal the last
                     * thread that releases the fd to close it.
                     */
          if (!closePending) {
            closePending = true;
            fdUseCount--;
            socketPreClose();
          }
        }
      }
    }
  }

  void reset() throws IOException {
    if (fd != null) {
      socketClose();
    }
    fd = null;
    super.reset();
  }


  /**
   * Shutdown read-half of the socket connection;
   */
  protected void shutdownInput() throws IOException {
    if (fd != null) {
      socketShutdown(SHUT_RD);
      if (socketInputStream != null) {
        socketInputStream.setEOF(true);
      }
      shut_rd = true;
    }
  }

  /**
   * Shutdown write-half of the socket connection;
   */
  protected void shutdownOutput() throws IOException {
    if (fd != null) {
      socketShutdown(SHUT_WR);
      shut_wr = true;
    }
  }

  protected boolean supportsUrgentData() {
    return true;
  }

  protected void sendUrgentData(int data) throws IOException {
    if (fd == null) {
      throw new IOException("Socket Closed");
    }
    socketSendUrgentData(data);
  }

  /**
   * Cleans up if the user forgets to close it.
   */
  protected void finalize() throws IOException {
    close();
  }

  /*
   * "Acquires" and returns the FileDescriptor for this impl
   *
   * A corresponding releaseFD is required to "release" the
   * FileDescriptor.
   */
  FileDescriptor acquireFD() {
    synchronized (fdLock) {
      fdUseCount++;
      return fd;
    }
  }

  /*
   * "Release" the FileDescriptor for this impl.
   *
   * If the use count goes to -1 then the socket is closed.
   */
  void releaseFD() {
    synchronized (fdLock) {
      fdUseCount--;
      if (fdUseCount == -1) {
        if (fd != null) {
          try {
            socketClose();
          } catch (IOException e) {
          } finally {
            fd = null;
          }
        }
      }
    }
  }

  public boolean isConnectionReset() {
    synchronized (resetLock) {
      return (resetState == CONNECTION_RESET);
    }
  }

  public boolean isConnectionResetPending() {
    synchronized (resetLock) {
      return (resetState == CONNECTION_RESET_PENDING);
    }
  }

  public void setConnectionReset() {
    synchronized (resetLock) {
      resetState = CONNECTION_RESET;
    }
  }

  public void setConnectionResetPending() {
    synchronized (resetLock) {
      if (resetState == CONNECTION_NOT_RESET) {
        resetState = CONNECTION_RESET_PENDING;
      }
    }

  }

  /*
   * Return true if already closed or close is pending
   */
  public boolean isClosedOrPending() {
        /*
         * Lock on fdLock to ensure that we wait if a
         * close is in progress.
         */
    synchronized (fdLock) {
      if (closePending || (fd == null)) {
        return true;
      } else {
        return false;
      }
    }
  }

  /*
   * Return the current value of SO_TIMEOUT
   */
  public int getTimeout() {
    return timeout;
  }

  /*
   * "Pre-close" a socket by dup'ing the file descriptor - this enables
   * the socket to be closed without releasing the file descriptor.
   */
  private void socketPreClose() throws IOException {
    socketClose0(true);
  }

  /*
   * Close the socket (and release the file descriptor).
   */
  protected void socketClose() throws IOException {
    socketClose0(false);
  }

  abstract void socketCreate(boolean isServer) throws IOException;

  abstract void socketConnect(InetAddress address, int port, int timeout)
      throws IOException;

  abstract void socketBind(InetAddress address, int port)
      throws IOException;

  abstract void socketListen(int count)
      throws IOException;

  abstract void socketAccept(SocketImpl s)
      throws IOException;

  abstract int socketAvailable()
      throws IOException;

  abstract void socketClose0(boolean useDeferredClose)
      throws IOException;

  abstract void socketShutdown(int howto)
      throws IOException;

  abstract void socketSetOption(int cmd, boolean on, Object value)
      throws SocketException;

  abstract int socketGetOption(int opt, Object iaContainerObj) throws SocketException;

  abstract void socketSendUrgentData(int data)
      throws IOException;

  public final static int SHUT_RD = 0;
  public final static int SHUT_WR = 1;
}
